An electronic control unit for activating the brakes and for exercising further functions is typically included in a vehicle with an electronic brake system. For this purpose, sensors and electromagnetic control valves are connected to the control unit. In addition, the control unit receives data by means of a CAN bus system or other data connection.
The transmission of control commands, the reading out of information and/or a configuration of the control unit are carried out by means of the data connection. For example, the angular position of a brake pedal for the operating brake is transmitted by means of the data connection. The control unit also signals the activity of an anti-lock function or selected sensor data to suitably located display units, for example in a driver's cab, by means of the data connection. Essentially, the driver in the driver's cab communicates with the control unit using provided displays and operating elements.
Trailer vehicles with electronic brake systems also comprise an electronic control unit, essentially with the aforementioned functions. Trailer-specific functions are also possible, for example automatic braking interventions in the event of unstable driving states or to prevent such states. Between the tractor vehicle and the trailer vehicle there are standardized connections that have to be plugged in when coupling the trailer vehicle, namely two pneumatic connections (supply pressure and control pressure) and an electrical connection that includes the data connection.
One hundred percent compatibility is desirable regarding the possibility to display the data from the control unit of the trailer vehicle and to influence the control unit of the trailer vehicle on the one hand with the relevant functions in the tractor vehicle on the other hand. In practice, such compatibility is not possible because trailer vehicles and tractor vehicles are arranged differently. Owing to different manufacturers and the user-selected functionalities, the control units in the trailer vehicle and tractor vehicle have different properties. Therefore, the provision of a display and operating unit for the driver is desirable, wherein the unit is connected to the control unit of the trailer vehicle.
When coupling the trailer vehicle to the tractor vehicle, confusion regarding the identity of the trailer vehicle must be avoided. In particular in large depots, identity confusion regarding the trailer vehicles can occur. More important is the definite identification of the trailer vehicle by the driver. The measures necessary for this should be able to be carried out rapidly and simply.
From WO 2013/124730 A1, it is known to couple a WLAN-compatible cell phone of the driver to the control unit of the trailer vehicle by means of a WLAN connection or a different wireless connection. In order to avoid an unwanted connection, such as to the smartphone of a driver that wants to pick up a different trailer vehicle, a list of permitted MAC addresses can be stored in a memory in the trailer vehicle. The MAC addresses are unique identifiers of WLAN-compatible terminals. Moreover, the trailer vehicle can transmit its own vehicle number and an SSID identifier of its own WLAN module. Confusion is however only excluded with the method if the driver makes additional entries to the smartphone or only a single MAC Address is stored in the memory of the trailer vehicle.